Geohydrology of the regional aquifer system, western Snake River plain, southwestern Idaho

Evaluation of seepage and discharge uncertainty in the middle Snake River, southwestern Idaho

“…1). The studies indicated regional movement of groundwater to the Snake River from various aquifers consisting of fractured basalt and intervening fine-grained sediment and gravels (Ralston and Chapman, 1968;Newton, 1991 Hortness and Vidmar (2005) noted that nearly all the seepage in this reach occurred upstream of Lower Salmon Falls Dam and that the highest seepage rate was measured in the reach between Buhl and Lower Salmon Falls Dam ( fig. 1), around the Thousand Springs Complex (not shown in fig.…”

“…1). Using a groundwater model, Newton (1991) estimated a gain in seepage of 461 ft 3 /s from groundwater to surface water in the reach between King Hill and Murphy. The gain in seepage estimated by Newton (1991) was about 4 percent of the average annual discharge of the Snake River at the Murphy streamgage.…”

“…Underlying aquifers, consisting primarily of sedimentary materials and fractured basalts, discharge to the middle Snake River downstream of King Hill through springs and subsurface inflows. Groundwater in the study area generally moves toward the Snake River (Lindholm and others, 1988;Newton, 1991).…”

“…Some of these hydrogeological studies (including Kjelstrom, 1986;Lindholm and others, 1988;and Newton, 1991) were completed as part of the USGS Regional Aquifer-System Analysis Program, starting in the late 1970s following a congressional mandate to develop quantitative assessments of major groundwater systems in the United States. Several other studies (including Ralston and Chapman, 1968;Norton and others, 1982;and Bendixsen, 1994) were completed as part of an effort to assess and protect "critical groundwater areas" in danger of overdevelopment and potential overappropriation of water resources near Mountain Home, Idaho ( fig.…”

Ambient water quality in aquifers used for drinking-water supplies, Gem County, southwestern Idaho, 2015

“…Western Snake River Plain RASA publications include depth to water maps (1980 conditions) (Lindholm and others, 1983;, a water budget (Kjelstrom, 1995), a geohydrologic framework (Whitehead, 1986), a map of irrigated lands and land use (1980 conditions) (Lindholm and Goodell, 1986), and steady-state and transient MODFLOW models (Newton, 1991). Following the RASA, Maupin (1991Maupin ( ) used 1980 data to construct a composite depth-to-water map for the western Snake River Plain, including much of the study area.…”